U.S. patent application number 17/450981 was filed with the patent office on 2022-04-21 for physical uplink control channel with adaptive demodulation reference signal density.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Tao LUO, Mahmoud TAHERZADEH BOROUJENI.
Application Number | 20220123896 17/450981 |
Document ID | / |
Family ID | 1000005917956 |
Filed Date | 2022-04-21 |
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United States Patent
Application |
20220123896 |
Kind Code |
A1 |
TAHERZADEH BOROUJENI; Mahmoud ;
et al. |
April 21, 2022 |
PHYSICAL UPLINK CONTROL CHANNEL WITH ADAPTIVE DEMODULATION
REFERENCE SIGNAL DENSITY
Abstract
A base station transmits to a user equipment (UE), an indication
of an adjustment to at least one of a density or a location of one
or more demodulation reference signals (DMRS) for at least one
physical uplink control channel (PUCCH) format. The base station
monitors for PUCCH based on the adjustment to the density or the
location of the DMRS indicated to the UE. A UE receives, from the
base station an indication of an adjustment to at least one of a
density or a location of one or more DMRS for at least one PUCCH
forma and transmits, to the base station, a PUCCH based on the
indication of the adjustment to at least one of the density or the
location of the one or more DMRS.
Inventors: |
TAHERZADEH BOROUJENI; Mahmoud;
(San Diego, CA) ; LUO; Tao; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005917956 |
Appl. No.: |
17/450981 |
Filed: |
October 14, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
63093069 |
Oct 16, 2020 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/14 20130101;
H04W 72/048 20130101; H04W 72/1284 20130101; H04L 5/0096 20130101;
H04L 5/0055 20130101; H04L 5/0051 20130101 |
International
Class: |
H04L 5/00 20060101
H04L005/00; H04W 72/04 20060101 H04W072/04; H04W 72/12 20060101
H04W072/12; H04W 72/14 20060101 H04W072/14 |
Claims
1. An apparatus for wireless communication of a base station,
comprising: memory; and at least one processor coupled to the
memory, the memory and the at least one processor configured to:
transmit, to a user equipment (UE), an indication of an adjustment
to at least one of a density or a location of one or more
demodulation reference signals (DMRS) for at least one physical
uplink control channel (PUCCH) format; and monitor for PUCCH based
on the adjustment to the density or the location of the DMRS
indicated to the UE.
2. The apparatus of claim 1, wherein the memory and the at least
one processor are further configured to: receive at least one of
channel state information (CSI) feedback or an uplink transmission
from the UE, the adjustment to the at least one of the density or
the location of the DMRS for the at least one PUCCH format being
based on the CSI feedback of the uplink transmission from the
UE.
3. The apparatus of claim 1, wherein the at least one PUCCH format
is a short PUCCH format including PUCCH format 2 or PUCCH format
3.
4. The apparatus of claim 1, wherein the adjustment to at least one
of the density or the location of the one or more DMRS corresponds
to a length adjustment of the at least one PUCCH format.
5. The apparatus of claim 1, wherein the adjustment to the density
of the one or more DMRS corresponds to an increase or a decrease in
a number of orthogonal frequency division multiplexing (OFDM)
symbols per slot.
6. The apparatus of claim 5, wherein the number of OFDM symbols per
slot is increased or decreased based on at least one of a coverage
enhancement indication or an acknowledgement (ACK) to a physical
downlink shared channel (PDSCH).
7. The apparatus of claim 1, wherein at least one of the density or
the location of the one or more DMRS corresponds to one or more
DMRS patterns.
8. The apparatus of claim 7, wherein the one or more DMRS patterns
are associated with a contiguous set of orthogonal frequency
division multiplexing (OFDM) symbols.
9. The apparatus of claim 1, wherein the memory and the at least
one processor are further configured to: receive, from the UE, the
PUCCH based on the indication of the adjustment to at least one of
the density or the location of the one or more DMRS.
10. The apparatus of claim 1, wherein the adjustment of the at
least one of the density or the location of the one or more DMRS is
further based on at least one of an uplink channel measurement, a
signal-to-interference plus noise ratio (SINR), or a hybrid
automatic repeat request (HARD) process.
11. The apparatus of claim 1, wherein the indication corresponds to
one of a set of reconfigurations for the at least one PUCCH
format.
12. The apparatus of claim 1, wherein the indication is transmitted
via at least one of UE-specific downlink control information (DCI),
group-common DCI, or a medium access control (MAC) control element
(MAC-CE).
13. The apparatus of claim 1, wherein the adjustment to at least
one of the density or the location of the one or more DMRS is
preconfigured or predefined.
14. The apparatus of claim 1, further comprising: at least one of
an antenna or a transceiver coupled to the at least one
processor.
15. A method of wireless communication of a base station,
comprising: transmitting, to a user equipment (UE), an indication
of an adjustment to at least one of a density or a location of one
or more demodulation reference signals (DMRS) for at least one
physical uplink control channel (PUCCH) format; and monitoring for
PUCCH based on the adjustment to the density or the location of the
DMRS indicated to the UE.
16. An apparatus of wireless communication of a user equipment
(UE), comprising: memory; and at least one processor coupled to the
memory, the memory and the at least one processor configured to:
receive, from a base station, an indication of an adjustment to at
least one of a density or a location of one or more demodulation
reference signals (DMRS) for at least one physical uplink control
channel (PUCCH) format; and transmit, to the base station, a PUCCH
based on the indication of the adjustment to at least one of the
density or the location of the one or more DMRS.
17. The apparatus of claim 16, wherein the memory and the at least
one processor are further configured to: transmit, to the base
station, at least one of channel state information (CSI) feedback
or an uplink transmission, the adjustment to the at least one of
the density or the location of the one or more DMRS for the at
least one PUCCH format being based on the CSI feedback or the
uplink transmission.
18. The apparatus of claim 16, wherein the at least one PUCCH
format is a short PUCCH format including PUCCH format 2 or PUCCH
format 3.
19. The apparatus of claim 16, wherein the adjustment to at least
one of the density or the location of the one or more DMRS
corresponds to a length adjustment of the at least one PUCCH
format.
20. The apparatus of claim 16, wherein the adjustment to the
density of the one or more DMRS corresponds to an increase or a
decrease in a number of orthogonal frequency division multiplexing
(OFDM) symbols per slot.
21. The apparatus of claim 20, wherein the number of OFDM symbols
per slot is increased or decreased based on at least one of a
coverage enhancement indication or an acknowledgement (ACK) to a
physical downlink shared channel (PDSCH).
22. The apparatus of claim 16, wherein at least one of the density
or the location of the one or more DMRS corresponds to one or more
DMRS patterns.
23. The apparatus of claim 22, wherein the one or more DMRS
patterns are associated with a contiguous set of orthogonal
frequency division multiplexing (OFDM) symbols.
24. The apparatus of claim 16, wherein the adjustment to at least
one of the density or the location of the one or more DMRS is based
on at least one of an uplink channel measurement, a
signal-to-interference plus noise ratio (SINR), or a hybrid
automatic repeat request (HARD) process.
25. The apparatus of claim 16, wherein the indication corresponds
to one of a set of reconfigurations for the at least one PUCCH
format.
26. The apparatus of claim 16, wherein the indication is received
via at least one of UE-specific downlink control information (DCI),
group-common DCI, or a medium access control (MAC) control element
(MAC-CE).
27. The apparatus of claim 16, wherein the adjustment to at least
one of the density or the location of the one or more DMRS is
preconfigured or predefined.
28. The apparatus of claim 16, further comprising: at least one of
an antenna or a transceiver coupled to the at least one
processor.
29. A method of wireless communication of a user equipment (UE),
comprising: receiving, from a base station, an indication of an
adjustment to at least one of a density or a location of one or
more demodulation reference signals (DMRS) for at least one
physical uplink control channel (PUCCH) format; and transmitting to
the base station a PUCCH based on the indication of the adjustment
to at least one of the density or the location of the one or more
DMRS.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of and priority to U.S.
Provisional Application Ser. No. 63/093,069, entitled "Physical
Uplink Control Channel With Adaptive Demodulation Reference Signal
Density" and filed on Oct. 16, 2020, which is expressly
incorporated by reference herein in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to communication
systems, and more particularly, to adjusting demodulation reference
signal (DMRS) density or location in one or more physical uplink
control channel (PUCCH) formats.
INTRODUCTION
[0003] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources. Examples of such multiple-access
technologies include code division multiple access (CDMA) systems,
time division multiple access (TDMA) systems, frequency division
multiple access (FDMA) systems, orthogonal frequency division
multiple access (OFDMA) systems, single-carrier frequency division
multiple access (SC-FDMA) systems, and time division synchronous
code division multiple access (TD-SCDMA) systems.
[0004] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. An example
telecommunication standard is 5G New Radio (NR). 5G NR is part of a
continuous mobile broadband evolution promulgated by Third
Generation Partnership Project (3GPP) to meet new requirements
associated with latency, reliability, security, scalability (e.g.,
with Internet of Things (IoT)), and other requirements. 5G NR
includes services associated with enhanced mobile broadband (eMBB),
massive machine type communications (mMTC), and ultra-reliable low
latency communications (URLLC). Some aspects of 5G NR may be based
on the 4G Long Term Evolution (LTE) standard. There exists a need
for further improvements in 5G NR technology. These improvements
may also be applicable to other multi-access technologies and the
telecommunication standards that employ these technologies.
BRIEF SUMMARY
[0005] The following presents a simplified summary of one or more
aspects in order to provide a basic understanding of such aspects.
This summary is not an extensive overview of all contemplated
aspects, and is intended to neither identify key or critical
elements of all aspects nor delineate the scope of any or all
aspects. Its sole purpose is to present some concepts of one or
more aspects in a simplified form as a prelude to the more detailed
description that is presented later.
[0006] Wireless communication may balance a tradeoff between
resource usage and increasing payload size. Wireless communication
with a shorter PUCCH format (e.g., PUCCH format 0 and format 2) may
be more vulnerable than longer PUCCH formats (e.g. PUCCH format 1,
format 3, or format 4) in terms of coverage, whereas longer PUCCH
formats may result in an unused payload and less efficient use of
wireless resources. For example, if a user equipment (UE) uses a
longer PUCCH format, the UE may use the same beam for additional
communication, even with changing channel conditions. However, the
use of a shorter PUCCH formats limits the payload.
[0007] Aspects presented herein enable the adaptation of PUCCH
communication within a slot (e.g., rather than for repetitions over
multiple slots). The adaptation may allow for an increased payload
over time with a more efficient use of wireless resource. For
example, using shorter PUCCH formats may enable faster beam
switching and a quicker response to changes in channel
conditions.
[0008] In an aspect of the disclosure, a method, a
computer-readable medium, and an apparatus for wireless
communication at a base station (BS) apparatus are provided. The
apparatus is configured to transmit, to a UE, an indication of an
adjustment to at least one of a density or a location of one or
more demodulation reference signals (DMRS) for at least one
physical uplink control channel (PUCCH) format. The apparatus is
configured to monitor for PUCCH based on the adjustment to the
density or the location of the DMRS indicated to the UE.
[0009] In an aspect of the disclosure, a method, a
computer-readable medium, an apparatus for wireless communication
at a UE are provided. The apparatus is configured to receive, from
a base station, an indication of an adjustment to at least one of a
density or a location of one or more DMRS for at least one PUCCH
format. The apparatus is configured to transmit, to the base
station, a PUCCH based on the indication of the adjustment to at
least one of the density or the location of the one or more
DMRS.
[0010] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a diagram illustrating an example of a wireless
communications system and an access network, in accordance with
various aspects of the present disclosure.
[0012] FIG. 2A is a diagram illustrating an example of a first
frame, in accordance with various aspects of the present
disclosure.
[0013] FIG. 2B is a diagram illustrating an example of DL channels
within a subframe, in accordance with various aspects of the
present disclosure.
[0014] FIG. 2C is a diagram illustrating an example of a second
frame, in accordance with various aspects of the present
disclosure.
[0015] FIG. 2D is a diagram illustrating an example of UL channels
within a subframe, in accordance with various aspects of the
present disclosure.
[0016] FIG. 3 is a diagram illustrating an example of a base
station and user equipment (UE) in an access network, in accordance
with various aspects of the present disclosure.
[0017] FIG. 4 is a diagram illustrating an example of communication
between a UE and a BS to dynamically adjust PUCCH format
communication, in accordance with various aspects of the present
disclosure.
[0018] FIG. 5A is a diagram illustrating an example DMRS used in a
short PUCCH format having a density, in accordance with various
aspects of the present disclosure.
[0019] FIG. 5B is a diagram illustrating an example adjustment to
the density of DMRS used in the short PUCCH format of FIG. 5A, in
accordance with various aspects of the present disclosure.
[0020] FIG. 5C is a diagram illustrating an example DMRS used in a
short PUCCH format having a particular location, in accordance with
various aspects of the present disclosure.
[0021] FIG. 5D is a diagram illustrating an example adjustment to
the location of DMRS used in the short PUCCH format of FIG. 5C, in
accordance with various aspects of the present disclosure.
[0022] FIGS. 6A and 6B are flowcharts of methods of wireless
communication at a UE, in accordance with various aspects of the
present disclosure.
[0023] FIG. 7 is a diagram illustrating an example of a hardware
implementation for an example UE apparatus, in accordance with
various aspects of the present disclosure.
[0024] FIGS. 8A and 8B are flowcharts of methods of wireless
communication at a base station, in accordance with various aspects
of the present disclosure.
[0025] FIG. 9 is a diagram illustrating an example of a hardware
implementation for an example BS apparatus, in accordance with
various aspects of the present disclosure.
DETAILED DESCRIPTION
[0026] Wireless communication may balance a tradeoff between
resource usage and increasing payload size. Wireless communication
with a shorter PUCCH format (e.g., PUCCH format 0 and format 2) may
be more vulnerable than longer PUCCH formats (e.g. PUCCH format 1,
format 3, or format 4) in terms of coverage, whereas longer PUCCH
formats may result in an unused payload and less efficient use of
wireless resources. For example, if a user equipment (UE) uses a
longer PUCCH format, the UE may use the same beam for additional
communication, even with changing channel conditions. However, the
use of a shorter PUCCH formats limits the payload.
[0027] Aspects presented herein enable the adaptation of PUCCH
communication within a slot (e.g., rather than for repetitions over
multiple slots). The adaptation may allow for an increased payload
over time with a more efficient use of wireless resource. For
example, using shorter PUCCH formats may enable faster beam
switching and a quicker response to changes in channel
conditions.
[0028] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0029] Several aspects of telecommunication systems will now be
presented with reference to various apparatus and methods. These
apparatus and methods will be described in the following detailed
description and illustrated in the accompanying drawings by various
blocks, components, circuits, processes, algorithms, etc.
(collectively referred to as "elements"). These elements may be
implemented using electronic hardware, computer software, or any
combination thereof. Whether such elements are implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system.
[0030] By way of example, an element, or any portion of an element,
or any combination of elements may be implemented as a "processing
system" that includes one or more processors. Examples of
processors include microprocessors, microcontrollers, graphics
processing units (GPUs), central processing units (CPUs),
application processors, digital signal processors (DSPs), reduced
instruction set computing (RISC) processors, systems on a chip
(SoC), baseband processors, field programmable gate arrays (FPGAs),
programmable logic devices (PLDs), state machines, gated logic,
discrete hardware circuits, and other suitable hardware configured
to perform the various functionality described throughout this
disclosure. One or more processors in the processing system may
execute software. Software shall be construed broadly to mean
instructions, instruction sets, code, code segments, program code,
programs, subprograms, software components, applications, software
applications, software packages, routines, subroutines, objects,
executables, threads of execution, procedures, functions, etc.,
whether referred to as software, firmware, middleware, microcode,
hardware description language, or otherwise.
[0031] Accordingly, in one or more example embodiments, the
functions described may be implemented in hardware, software, or
any combination thereof. If implemented in software, the functions
may be stored on or encoded as one or more instructions or code on
a computer-readable medium. Computer-readable media includes
computer storage media. Storage media may be any available media
that can be accessed by a computer. By way of example, and not
limitation, such computer-readable media can comprise a
random-access memory (RAM), a read-only memory (ROM), an
electrically erasable programmable ROM (EEPROM), optical disk
storage, magnetic disk storage, other magnetic storage devices,
combinations of the types of computer-readable media, or any other
medium that can be used to store computer executable code in the
form of instructions or data structures that can be accessed by a
computer.
[0032] While aspects and implementations are described in this
application by illustration to some examples, those skilled in the
art will understand that additional implementations and use cases
may come about in many different arrangements and scenarios.
Aspects described herein may be implemented across many differing
platform types, devices, systems, shapes, sizes, and packaging
arrangements. For example, implementations and/or uses may come
about via integrated chip implementations and other
non-module-component based devices (e.g., end-user devices,
vehicles, communication devices, computing devices, industrial
equipment, retail/purchasing devices, medical devices, artificial
intelligence (AI)-enabled devices, etc.). While some examples may
or may not be specifically directed to use cases or applications, a
wide assortment of applicability of described aspects may occur.
Implementations may range a spectrum from chip-level or modular
components to non-modular, non-chip-level implementations and
further to aggregate, distributed, or original equipment
manufacturer (OEM) devices or systems incorporating one or more
aspects of the described aspects. In some practical settings,
devices incorporating described aspects and features may also
include additional components and features for implementation and
practice of claimed and described aspect. For example, transmission
and reception of wireless signals necessarily includes a number of
components for analog and digital purposes (e.g., hardware
components including antenna, RF-chains, power amplifiers,
modulators, buffer, processor(s), interleaver, adders/summers,
etc.). It is intended that aspects described herein may be
practiced in a wide variety of devices, chip-level components,
systems, distributed arrangements, aggregated or disaggregated
components, end-user devices, etc. of varying sizes, shapes, and
constitution.
[0033] FIG. 1 is a diagram illustrating an example of a wireless
communications system and an access network 100. The wireless
communications system (also referred to as a wireless wide area
network (WWAN)) includes base stations 102, UEs 104, an Evolved
Packet Core (EPC) 160, and another core network 190 (e.g., a 5G
Core (5GC)). The base stations 102 may include macrocells (high
power cellular base station) and/or small cells (low power cellular
base station). The macrocells include base stations. The small
cells include femtocells, picocells, and microcells.
[0034] The base stations 102 configured for 4G LTE (collectively
referred to as Evolved Universal Mobile Telecommunications System
(UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface
with the EPC 160 through first backhaul links 132 (e.g., S1
interface). The base stations 102 configured for 5G NR
(collectively referred to as Next Generation RAN (NG-RAN)) may
interface with core network 190 through second backhaul links 184.
In addition to other functions, the base stations 102 may perform
one or more of the following functions: transfer of user data,
radio channel ciphering and deciphering, integrity protection,
header compression, mobility control functions (e.g., handover,
dual connectivity), inter-cell interference coordination,
connection setup and release, load balancing, distribution for
non-access stratum (NAS) messages, NAS node selection,
synchronization, radio access network (RAN) sharing, multimedia
broadcast multicast service (MBMS), subscriber and equipment trace,
RAN information management (RIM), paging, positioning, and delivery
of warning messages. The base stations 102 may communicate directly
or indirectly (e.g., through the EPC 160 or core network 190) with
each other over third backhaul links 134 (e.g., X2 interface). The
first backhaul links 132, the second backhaul links 184, and the
third backhaul links 134 may be wired or wireless.
[0035] The base stations 102 may wirelessly communicate with the
UEs 104. Each of the base stations 102 may provide communication
coverage for a respective geographic coverage area 110. There may
be overlapping geographic coverage areas 110. For example, the
small cell 102' may have a coverage area 110' that overlaps the
coverage area 110 of one or more macro base stations 102. A network
that includes both small cell and macrocells may be known as a
heterogeneous network. A heterogeneous network may also include
Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a
restricted group known as a closed subscriber group (CSG). The
communication links 120 between the base stations 102 and the UEs
104 may include uplink (UL) (also referred to as reverse link)
transmissions from a UE 104 to a base station 102 and/or downlink
(DL) (also referred to as forward link) transmissions from a base
station 102 to a UE 104. The communication links 120 may use
multiple-input and multiple-output (MIMO) antenna technology,
including spatial multiplexing, beamforming, and/or transmit
diversity. The communication links may be through one or more
carriers. The base stations 102/UEs 104 may use spectrum up to Y
MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier
allocated in a carrier aggregation of up to a total of Yx MHz (x
component carriers) used for transmission in each direction. The
carriers may or may not be adjacent to each other. Allocation of
carriers may be asymmetric with respect to DL and UL (e.g., more or
fewer carriers may be allocated for DL than for UL). The component
carriers may include a primary component carrier and one or more
secondary component carriers. A primary component carrier may be
referred to as a primary cell (PCell) and a secondary component
carrier may be referred to as a secondary cell (SCell).
[0036] Certain UEs 104 may communicate with each other using
device-to-device (D2D) communication link 158. The D2D
communication link 158 may use the DL/UL WWAN spectrum. The D2D
communication link 158 may use one or more sidelink channels, such
as a physical sidelink broadcast channel (PSBCH), a physical
sidelink discovery channel (PSDCH), a physical sidelink shared
channel (PSSCH), and a physical sidelink control channel (PSCCH).
D2D communication may be through a variety of wireless D2D
communications systems, such as for example, WiMedia, Bluetooth,
ZigBee, Wi-Fi based on the Institute of Electrical and Electronics
Engineers (IEEE) 802.11 standard, LTE, or NR.
[0037] The wireless communications system may further include a
Wi-Fi access point (AP) 150 in communication with Wi-Fi stations
(STAs) 152 via communication links 154, e.g., in a 5 GHz unlicensed
frequency spectrum or the like. When communicating in an unlicensed
frequency spectrum, the STAs 152/AP 150 may perform a clear channel
assessment (CCA) prior to communicating in order to determine
whether the channel is available.
[0038] The small cell 102' may operate in a licensed and/or an
unlicensed frequency spectrum. When operating in an unlicensed
frequency spectrum, the small cell 102' may employ NR and use the
same unlicensed frequency spectrum (e.g., 5 GHz, or the like) as
used by the Wi-Fi AP 150. The small cell 102', employing NR in an
unlicensed frequency spectrum, may boost coverage to and/or
increase capacity of the access network.
[0039] The electromagnetic spectrum is often subdivided, based on
frequency/wavelength, into various classes, bands, channels, etc.
In 5G NR, two initial operating bands have been identified as
frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25
GHz-52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1
is often referred to (interchangeably) as a "sub-6 GHz" band in
various documents and articles. A similar nomenclature issue
sometimes occurs with regard to FR2, which is often referred to
(interchangeably) as a "millimeter wave" band in documents and
articles, despite being different from the extremely high frequency
(EHF) band (30 GHz-300 GHz) which is identified by the
International Telecommunications Union (ITU) as a "millimeter wave"
band.
[0040] The frequencies between FR1 and FR2 are often referred to as
mid-band frequencies. Recent 5G NR studies have identified an
operating band for these mid-band frequencies as frequency range
designation FR3 (7.125 GHz-24.25 GHz). Frequency bands falling
within FR3 may inherit FR1 characteristics and/or FR2
characteristics, and thus may effectively extend features of FR1
and/or FR2 into mid-band frequencies. In addition, higher frequency
bands are currently being explored to extend 5G NR operation beyond
52.6 GHz. For example, three higher operating bands have been
identified as frequency range designations FR2-2 (52.6 GHz-71 GHz),
FR4 (52.6 GHz-114.25 GHz), and FR5 (114.25 GHz-300 GHz). Each of
these higher frequency bands falls within the EHF band.
[0041] With the above aspects in mind, unless specifically stated
otherwise, it should be understood that the term "sub-6 GHz" or the
like if used herein may broadly represent frequencies that may be
less than 6 GHz, may be within FR1, or may include mid-band
frequencies. Further, unless specifically stated otherwise, it
should be understood that the term "millimeter wave" or the like if
used herein may broadly represent frequencies that may include
mid-band frequencies, may be within FR2, FR4, FR2-2, and/or FR5, or
may be within the EHF band.
[0042] A base station 102, whether a small cell 102' or a large
cell (e.g., macro base station), may include and/or be referred to
as an eNB, gNodeB (gNB), or another type of base station. Some base
stations, such as gNB 180 may operate in a traditional sub 6 GHz
spectrum, in millimeter wave frequencies, and/or near millimeter
wave frequencies in communication with the UE 104. When the gNB 180
operates in millimeter wave or near millimeter wave frequencies,
the gNB 180 may be referred to as a millimeter wave base station.
The millimeter wave base station 180 may utilize beamforming 182
with the UE 104 to compensate for the path loss and short range.
The base station 180 and the UE 104 may each include a plurality of
antennas, such as antenna elements, antenna panels, and/or antenna
arrays to facilitate the beamforming.
[0043] The base station 180 may transmit a beamformed signal to the
UE 104 in one or more transmit directions 182'. The UE 104 may
receive the beamformed signal from the base station 180 in one or
more receive directions 182''. The UE 104 may also transmit a
beamformed signal to the base station 180 in one or more transmit
directions. The base station 180 may receive the beamformed signal
from the UE 104 in one or more receive directions. The base station
180/UE 104 may perform beam training to determine the best receive
and transmit directions for each of the base station 180/UE 104.
The transmit and receive directions for the base station 180 may or
may not be the same. The transmit and receive directions for the UE
104 may or may not be the same.
[0044] The EPC 160 may include a Mobility Management Entity (MME)
162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast
Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service
Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172.
The MME 162 may be in communication with a Home Subscriber Server
(HSS) 174. The MME 162 is the control node that processes the
signaling between the UEs 104 and the EPC 160. Generally, the MME
162 provides bearer and connection management. All user Internet
protocol (IP) packets are transferred through the Serving Gateway
166, which itself is connected to the PDN Gateway 172. The PDN
Gateway 172 provides UE IP address allocation as well as other
functions. The PDN Gateway 172 and the BM-SC 170 are connected to
the IP Services 176. The IP Services 176 may include the Internet,
an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming
Service, and/or other IP services. The BM-SC 170 may provide
functions for MBMS user service provisioning and delivery. The
BM-SC 170 may serve as an entry point for content provider MBMS
transmission, may be used to authorize and initiate MBMS Bearer
Services within a public land mobile network (PLMN), and may be
used to schedule MBMS transmissions. The MBMS Gateway 168 may be
used to distribute MBMS traffic to the base stations 102 belonging
to a Multicast Broadcast Single Frequency Network (MBSFN) area
broadcasting a particular service, and may be responsible for
session management (start/stop) and for collecting eMBMS related
charging information.
[0045] The core network 190 may include an Access and Mobility
Management Function (AMF) 192, other AMFs 193, a Session Management
Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF
192 may be in communication with a Unified Data Management (UDM)
196. The AMF 192 is the control node that processes the signaling
between the UEs 104 and the core network 190. Generally, the AMF
192 provides QoS flow and session management. All user Internet
protocol (IP) packets are transferred through the UPF 195. The UPF
195 provides UE IP address allocation as well as other functions.
The UPF 195 is connected to the IP Services 197. The IP Services
197 may include the Internet, an intranet, an IP Multimedia
Subsystem (IMS), a Packet Switch (PS) Streaming (PSS) Service,
and/or other IP services.
[0046] The base station may include and/or be referred to as a gNB,
Node B, eNB, an access point, a base transceiver station, a radio
base station, a radio transceiver, a transceiver function, a basic
service set (BSS), an extended service set (ESS), a transmit
reception point (TRP), or some other suitable terminology. The base
station 102 provides an access point to the EPC 160 or core network
190 for a UE 104. Examples of UEs 104 include a cellular phone, a
smart phone, a session initiation protocol (SIP) phone, a laptop, a
personal digital assistant (PDA), a satellite radio, a global
positioning system, a multimedia device, a video device, a digital
audio player (e.g., MP3 player), a camera, a game console, a
tablet, a smart device, a wearable device, a vehicle, an electric
meter, a gas pump, a large or small kitchen appliance, a healthcare
device, an implant, a sensor/actuator, a display, or any other
similar functioning device. Some of the UEs 104 may be referred to
as IoT devices (e.g., parking meter, gas pump, toaster, vehicles,
heart monitor, etc.). The UE 104 may also be referred to as a
station, a mobile station, a subscriber station, a mobile unit, a
subscriber unit, a wireless unit, a remote unit, a mobile device, a
wireless device, a wireless communications device, a remote device,
a mobile subscriber station, an access terminal, a mobile terminal,
a wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, a client, or some other suitable terminology. In
some scenarios, the term UE may also apply to one or more companion
devices such as in a device constellation arrangement. One or more
of these devices may collectively access the network and/or
individually access the network.
[0047] Referring again to FIG. 1, in certain aspects, the UE 104
may be configured with a PUCCH component (198) that is configured
to adjust the density or location of the DMRS for one or more PUCCH
formats. In certain aspects, the base station 180 may be configured
to with a PUCCH component (199) that is configured to determine to
adjust the density or location of the DMRS for one or more PUCCH
formats and send an indication to the UE to adjust the density or
location of the DMRS for one or more PUCCH formats. Although the
following description may be focused on 5G NR, the concepts
described herein may be applicable to other similar areas, such as
LTE, LTE-A, CDMA, GSM, and other wireless technologies.
[0048] FIG. 2A is a diagram 200 illustrating an example of a first
subframe within a 5G NR frame structure. FIG. 2B is a diagram 230
illustrating an example of DL channels within a 5G NR subframe.
FIG. 2C is a diagram 250 illustrating an example of a second
subframe within a 5G NR frame structure. FIG. 2D is a diagram 280
illustrating an example of UL channels within a 5G NR subframe. The
5G NR frame structure may be frequency division duplexed (FDD) in
which for a particular set of subcarriers (carrier system
bandwidth), subframes within the set of subcarriers are dedicated
for either DL or UL, or may be time division duplexed (TDD) in
which for a particular set of subcarriers (carrier system
bandwidth), subframes within the set of subcarriers are dedicated
for both DL and UL. In the examples provided by FIGS. 2A, 2C, the
5G NR frame structure is assumed to be TDD, with subframe 4 being
configured with slot format 28 (with mostly DL), where D is DL, U
is UL, and F is flexible for use between DL/UL, and subframe 3
being configured with slot format 1 (with all UL). While subframes
3, 4 are shown with slot formats 1, 28, respectively, any
particular subframe may be configured with any of the various
available slot formats 0-61. Slot formats 0, 1 are all DL, UL,
respectively. Other slot formats 2-61 include a mix of DL, UL, and
flexible symbols. UEs are configured with the slot format
(dynamically through DL control information (DCI), or
semi-statically/statically through radio resource control (RRC)
signaling) through a received slot format indicator (SFI). Note
that the description infra applies also to a 5G NR frame structure
that is TDD.
[0049] FIGS. 2A-2D illustrate a frame structure, and the aspects of
the present disclosure may be applicable to other wireless
communication technologies, which may have a different frame
structure and/or different channels. A frame (10 ms) may be divided
into 10 equally sized subframes (1 ms). Each subframe may include
one or more time slots. Subframes may also include mini-slots,
which may include 7, 4, or 2 symbols. Each slot may include 14 or
12 symbols, depending on whether the cyclic prefix (CP) is normal
or extended. For normal CP, each slot may include 14 symbols, and
for extended CP, each slot may include 12 symbols. The symbols on
DL may be CP orthogonal frequency division multiplexing (OFDM)
(CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for
high throughput scenarios) or discrete Fourier transform (DFT)
spread OFDM (DFT-s-OFDM) symbols (also referred to as single
carrier frequency-division multiple access (SC-FDMA) symbols) (for
power limited scenarios; limited to a single stream transmission).
The number of slots within a subframe is based on the CP and the
numerology. The numerology defines the subcarrier spacing (SCS)
and, effectively, the symbol length/duration, which is equal to
1/SCS.
TABLE-US-00001 .mu. SCS .DELTA.f = 2.sup..mu. 15[kHz] Cyclic prefix
0 15 Normal 1 30 Normal 2 60 Normal, Extended 3 120 Normal 4 240
Normal
[0050] For normal CP (14 symbols/slot), different numerologies
.mu.0 to 4 allow for 1, 2, 4, 8, and 16 slots, respectively, per
subframe. For extended CP, the numerology 2 allows for 4 slots per
subframe. Accordingly, for normal CP and numerology .mu., there are
14 symbols/slot and 2.sup..mu. slots/subframe. The subcarrier
spacing may be equal to 2.sup..mu.*15 kHz, where .mu. is the
numerology 0 to 4. As such, the numerology .mu.=0 has a subcarrier
spacing of 15 kHz and the numerology .mu.=4 has a subcarrier
spacing of 240 kHz. The symbol length/duration is inversely related
to the subcarrier spacing. FIGS. 2A-2D provide an example of normal
CP with 14 symbols per slot and numerology .mu.=2 with 4 slots per
subframe. The slot duration is 0.25 ms, the subcarrier spacing is
60 kHz, and the symbol duration is approximately 16.67 .mu.s.
Within a set of frames, there may be one or more different
bandwidth parts (BWPs) (see FIG. 2B) that are frequency division
multiplexed. Each BWP may have a particular numerology and CP
(normal or extended).
[0051] A resource grid may be used to represent the frame
structure. Each time slot includes a resource block (RB) (also
referred to as physical RBs (PRBs)) that extends 12 consecutive
subcarriers. The resource grid is divided into multiple resource
elements (REs). The number of bits carried by each RE depends on
the modulation scheme.
[0052] As illustrated in FIG. 2A, some of the REs carry reference
(pilot) signals (RS) for the UE. The RS may include demodulation RS
(DM-RS) (indicated as R for one particular configuration, but other
DM-RS configurations are possible) and channel state information
reference signals (CSI-RS) for channel estimation at the UE. The RS
may also include beam measurement RS (BRS), beam refinement RS
(BRRS), and phase tracking RS (PT-RS).
[0053] FIG. 2B illustrates an example of various DL channels within
a subframe of a frame. The physical downlink control channel
(PDCCH) carries DCI within one or more control channel elements
(CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six RE
groups (REGs), each REG including 12 consecutive REs in an OFDM
symbol of an RB. A PDCCH within one BWP may be referred to as a
control resource set (CORESET). A UE is configured to monitor PDCCH
candidates in a PDCCH search space (e.g., common search space,
UE-specific search space) during PDCCH monitoring occasions on the
CORESET, where the PDCCH candidates have different DCI formats and
different aggregation levels. Additional BWPs may be located at
greater and/or lower frequencies across the channel bandwidth. A
primary synchronization signal (PSS) may be within symbol 2 of
particular subframes of a frame. The PSS is used by a UE 104 to
determine subframe/symbol timing and a physical layer identity. A
secondary synchronization signal (SSS) may be within symbol 4 of
particular subframes of a frame. The SSS is used by a UE to
determine a physical layer cell identity group number and radio
frame timing. Based on the physical layer identity and the physical
layer cell identity group number, the UE can determine a physical
cell identifier (PCI). Based on the PCI, the UE can determine the
locations of the DM-RS. The physical broadcast channel (PBCH),
which carries a master information block (MIB), may be logically
grouped with the PSS and SSS to form a synchronization signal
(SS)/PBCH block (also referred to as SS block (SSB)). The MIB
provides a number of RBs in the system bandwidth and a system frame
number (SFN). The physical downlink shared channel (PDSCH) carries
user data, broadcast system information not transmitted through the
PBCH such as system information blocks (SIBs), and paging
messages.
[0054] As illustrated in FIG. 2C, some of the REs carry DM-RS
(indicated as R for one particular configuration, but other DM-RS
configurations are possible) for channel estimation at the base
station. The UE may transmit DM-RS for the physical uplink control
channel (PUCCH) and DM-RS for the physical uplink shared channel
(PUSCH). The PUSCH DM-RS may be transmitted in the first one or two
symbols of the PUSCH. The PUCCH DM-RS may be transmitted in
different configurations depending on whether short or long PUCCHs
are transmitted and depending on the particular PUCCH format used.
The UE may transmit sounding reference signals (SRS). The SRS may
be transmitted in the last symbol of a subframe. The SRS may have a
comb structure, and a UE may transmit SRS on one of the combs. The
SRS may be used by a base station for channel quality estimation to
enable frequency-dependent scheduling on the UL.
[0055] FIG. 2D illustrates an example of various UL channels within
a subframe of a frame. The PUCCH may be located as indicated in one
configuration. The PUCCH carries uplink control information (UCI),
such as scheduling requests, a channel quality indicator (CQI), a
precoding matrix indicator (PMI), a rank indicator (RI), and hybrid
automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK)
feedback (i.e., one or more HARQ ACK bits indicating one or more
ACK and/or negative ACK (NACK)). The PUSCH carries data, and may
additionally be used to carry a buffer status report (BSR), a power
headroom report (PHR), and/or UCI.
[0056] FIG. 3 is a block diagram of a base station 310 in
communication with a UE 350 in an access network. In the DL, IP
packets from the EPC 160 may be provided to a controller/processor
375. The controller/processor 375 implements layer 3 and layer 2
functionality. Layer 3 includes a radio resource control (RRC)
layer, and layer 2 includes a service data adaptation protocol
(SDAP) layer, a packet data convergence protocol (PDCP) layer, a
radio link control (RLC) layer, and a medium access control (MAC)
layer. The controller/processor 375 provides RRC layer
functionality associated with broadcasting of system information
(e.g., MIB, SIBs), RRC connection control (e.g., RRC connection
paging, RRC connection establishment, RRC connection modification,
and RRC connection release), inter radio access technology (RAT)
mobility, and measurement configuration for UE measurement
reporting; PDCP layer functionality associated with header
compression/decompression, security (ciphering, deciphering,
integrity protection, integrity verification), and handover support
functions; RLC layer functionality associated with the transfer of
upper layer packet data units (PDUs), error correction through ARQ,
concatenation, segmentation, and reassembly of RLC service data
units (SDUs), re-segmentation of RLC data PDUs, and reordering of
RLC data PDUs; and MAC layer functionality associated with mapping
between logical channels and transport channels, multiplexing of
MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs
from TBs, scheduling information reporting, error correction
through HARQ, priority handling, and logical channel
prioritization.
[0057] The transmit (TX) processor 316 and the receive (RX)
processor 370 implement layer 1 functionality associated with
various signal processing functions. Layer 1, which includes a
physical (PHY) layer, may include error detection on the transport
channels, forward error correction (FEC) coding/decoding of the
transport channels, interleaving, rate matching, mapping onto
physical channels, modulation/demodulation of physical channels,
and MIMO antenna processing. The TX processor 316 handles mapping
to signal constellations based on various modulation schemes (e.g.,
binary phase-shift keying (BPSK), quadrature phase-shift keying
(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude
modulation (M-QAM)). The coded and modulated symbols may then be
split into parallel streams. Each stream may then be mapped to an
OFDM subcarrier, multiplexed with a reference signal (e.g., pilot)
in the time and/or frequency domain, and then combined together
using an Inverse Fast Fourier Transform (IFFT) to produce a
physical channel carrying a time domain OFDM symbol stream. The
OFDM stream is spatially precoded to produce multiple spatial
streams. Channel estimates from a channel estimator 374 may be used
to determine the coding and modulation scheme, as well as for
spatial processing. The channel estimate may be derived from a
reference signal and/or channel condition feedback transmitted by
the UE 350. Each spatial stream may then be provided to a different
antenna 320 via a separate transmitter 318 TX. Each transmitter 318
TX may modulate an RF carrier with a respective spatial stream for
transmission.
[0058] At the UE 350, each receiver 354 RX receives a signal
through its respective antenna 352. Each receiver 354 RX recovers
information modulated onto an RF carrier and provides the
information to the receive (RX) processor 356. The TX processor 368
and the RX processor 356 implement layer 1 functionality associated
with various signal processing functions. The RX processor 356 may
perform spatial processing on the information to recover any
spatial streams destined for the UE 350. If multiple spatial
streams are destined for the UE 350, they may be combined by the RX
processor 356 into a single OFDM symbol stream. The RX processor
356 then converts the OFDM symbol stream from the time-domain to
the frequency domain using a Fast Fourier Transform (FFT). The
frequency domain signal comprises a separate OFDM symbol stream for
each subcarrier of the OFDM signal. The symbols on each subcarrier,
and the reference signal, are recovered and demodulated by
determining the most likely signal constellation points transmitted
by the base station 310. These soft decisions may be based on
channel estimates computed by the channel estimator 358. The soft
decisions are then decoded and deinterleaved to recover the data
and control signals that were originally transmitted by the base
station 310 on the physical channel. The data and control signals
are then provided to the controller/processor 359, which implements
layer 3 and layer 2 functionality.
[0059] The controller/processor 359 can be associated with a memory
360 that stores program codes and data. The memory 360 may be
referred to as a computer-readable medium. In the UL, the
controller/processor 359 provides demultiplexing between transport
and logical channels, packet reassembly, deciphering, header
decompression, and control signal processing to recover IP packets
from the EPC 160. The controller/processor 359 is also responsible
for error detection using an ACK and/or NACK protocol to support
HARQ operations.
[0060] Similar to the functionality described in connection with
the DL transmission by the base station 310, the
controller/processor 359 provides RRC layer functionality
associated with system information (e.g., MIB, SIBs) acquisition,
RRC connections, and measurement reporting; PDCP layer
functionality associated with header compression/decompression, and
security (ciphering, deciphering, integrity protection, integrity
verification); RLC layer functionality associated with the transfer
of upper layer PDUs, error correction through ARQ, concatenation,
segmentation, and reassembly of RLC SDUs, re-segmentation of RLC
data PDUs, and reordering of RLC data PDUs; and MAC layer
functionality associated with mapping between logical channels and
transport channels, multiplexing of MAC SDUs onto TBs,
demultiplexing of MAC SDUs from TBs, scheduling information
reporting, error correction through HARQ, priority handling, and
logical channel prioritization.
[0061] Channel estimates derived by a channel estimator 358 from a
reference signal or feedback transmitted by the base station 310
may be used by the TX processor 368 to select the appropriate
coding and modulation schemes, and to facilitate spatial
processing. The spatial streams generated by the TX processor 368
may be provided to different antenna 352 via separate transmitters
354TX. Each transmitter 354TX may modulate an RF carrier with a
respective spatial stream for transmission.
[0062] The UL transmission is processed at the base station 310 in
a manner similar to that described in connection with the receiver
function at the UE 350. Each receiver 318RX receives a signal
through its respective antenna 320. Each receiver 318RX recovers
information modulated onto a radio frequency (RF) carrier and
provides the information to a RX processor 370.
[0063] The controller/processor 375 can be associated with a memory
376 that stores program codes and data. The memory 376 may be
referred to as a computer-readable medium. In the UL, the
controller/processor 375 provides demultiplexing between transport
and logical channels, packet reassembly, deciphering, header
decompression, control signal processing to recover IP packets from
the UE 350. IP packets from the controller/processor 375 may be
provided to the EPC 160. The controller/processor 375 is also
responsible for error detection using an ACK and/or NACK protocol
to support HARQ operations.
[0064] At least one of the TX processor 368, the RX processor 356,
and the controller/processor 359 may be configured to perform
aspects in connection with the PUCCH component 198 of FIG. 1.
[0065] At least one of the TX processor 316, the RX processor 370,
and the controller/processor 375 may be configured to perform
aspects in connection with the PUCCH component 199 of FIG. 1.
[0066] Coverage enhancements for PUCCH may improve wireless
communications, especially for larger payload sizes. In wireless
communications, short PUCCH formats such as PUCCH format 0 and
format 2 may be more vulnerable in terms of coverage. Yet, relying
on longer PUCCH formats may lead to less efficient resource usage.
Wireless communication with a shorter PUCCH format (e.g., PUCCH
format 0 and format 2) may be more vulnerable than longer PUCCH
formats (e.g. PUCCH format 1, format 3, or format 4) in terms of
coverage, whereas longer PUCCH formats may result in an unused
payload and less efficient use of wireless resources. For example,
if a user equipment (UE) uses a longer PUCCH format, the UE may use
the same beam for additional communication, even with changing
channel conditions. However, the use of a shorter PUCCH formats
limits the payload.
[0067] Table 1 illustrates an example of PUCCH formats and example
lengths and numbers of bits. Table 1 is merely an example to
illustrate an example comparison of different sizes of PUCCH
formats. The aspects presented herein are not limited to
application to the PUCCH formats described in Table 1.
TABLE-US-00002 TABLE 1 Length in PUCCH #OFDM #UCI format symbols
bits Waveform Description 0 1-2 .ltoreq.2 CGS seq Short PUCCH
format with 1-2 bits UCI 1 4-14 .ltoreq.2 CGS seq Long PUCCH format
with 1-2 bits UCI (TD- OCC) 2 1-2 >2 OFDM Short PUCCH format
with >2 bits UCI 3 4-14 >2 DFT-S-OFDM Long PUCCH format with
>2- bits UCI and no multiplexing capability 4 4-14 >2
DFT-S-OFDM Long PUCCH format with >2- bits UCI and multiplexing
capability
[0068] Aspects presented herein enable the adaptation of PUCCH
communication within a slot (e.g., rather than for repetitions over
multiple slots). The adaptation may allow for an increased payload
over time with a more efficient use of wireless resource. For
example, using shorter PUCCH formats may enable faster beam
switching and a quicker response to changes in channel conditions.
This adjustment/adaptation of the PUCCH communication may improve
use of wireless resources during a variety of different channel
conditions. For example, using shorter PUCCH formats may allow for
faster beam switching when a base station is serving multiple
UEs.
[0069] FIG. 4 is a diagram 400 illustrating an example of
communication between a UE 402 and a base station 404 to
dynamically adjust PUCCH format communication. Initially, at 406
the UE 402 transmits CSI feedback or an UL transmission to the base
station 404. At 408, the base station 404 evaluates the CSI
feedback or the UL information to determine whether or not to
adjust a density or a location of DMRS for at least one PUCCH
format. For example, at 408 the base station 404 may determine to
adjust the DMRS density of a PUCCH format based on an estimated
signal to interference and noise ratio (SINR) and/or CSI feedback
and/or quality of uplink reception and/or HARQ history information.
Additionally, the base station 404 may change the density and/or
location of DMRS for at least one PUCCH format, for example, PUCCH
format 2 and/or format 0 and/or format 3.
[0070] In one aspect, a determination by the base station 404 to
change a DMRS density and/or location may be linked to a change of
the length of PUCCH format 2, based on certain specifications
and/or configurations by the BS, e.g., via RRC signaling.
Additionally, the density and/or location of DMRS of the PUCCH
format may be dynamically changed by the base station 404, for
example, by selecting among a set of options defined in certain
specifications.
[0071] At 410, the base station 404 transmits an adjustment
indication to the UE. This transmission may be transmitted by
downlink control information (DCI) or other UE-specific
transmission and/or by group-common DCI (GC-DCI) and/or by downlink
medium access control (MAC) control element (CE)(MAC-CE). In the
transmission, the base station 404 may explicitly indicate the
pattern of DMRS, for example, indicating a pattern among a set of
options defined in certain specifications. In some aspects, the
change of the DMRS density and/or location may be configured by the
base station, e.g., in RRC signaling. The DCI or MAC-CE may then
indication the density/location of the DMRS configured via the RRC
signaling.
[0072] In alternative aspects, the adjustment indication 410 may be
a dynamic indication for the UE to switch among a set of
reconfigurations for a PUCCH or may be an implicit dynamic
indication for the UE to adjust based on another signaling. For
example, in one aspect the density and/or location of DMRS for a
PUCCH may be adjusted by the dynamic indication and the number of
its OFDM symbols increased based on receiving a
coverage-enhancement indication. In another aspect the density
and/or location of DMRS for a PUCCH may be adjusted and the number
of its OFDM symbols may be increased if it contains an ACK in
response to a PDSCH that carries a beam-switching MAC-CE.
[0073] In one aspect, certain DMRS patterns may be valid when PUCCH
is transmitted over a contiguous set of OFDM symbols, which may be
particularly helpful if a short PUCCH over a large number of
noncontiguous OFDM symbols is utilized.
[0074] At 412, after receiving the adjustment indication, the UE
402 configures the density or location of the DMRS for the PUCCH
format in accordance with the adjustment indication. At 414, the UE
402 transmits PUCCH information using the adjusted density or
location of the DMRS for the PUCCH format.
[0075] FIGS. 5A, 5B, 5C and 5D are diagrams illustrating an example
adjustment to the density and location of DMRS used in a short
PUCCH format. In one aspect, a short PUCCH (e.g., 1-2 OFDM symbols)
may have a UCI payload of less than or equal to two bits. For a
1-symbol short PUCCH with a UCI payload of less than or equal to
two bits, with or without a scheduling request (SR), sequence
selection may use low peak-to-average-power ratio (PAPR). For
simultaneous transmission of a two-bit hybrid automatic repeat
request (HARQ)-acknowledgement (ACK)(HARQ-ACK) and SRs, a PUCCH
format 0 may be used. Computer generated sequences (CGSs) having a
length 12 with consecutive mapping within a PRB may be supported.
Additionally, the supported number of base sequences may be at
least 30. Additionally, the number of cyclic shifts available for
one base sequence may be at least 12.
[0076] For a 2-symbol short PUCCH with a UCI payload less than or
equal to two bits, with or without SR, a 2-symbol PUCCH may be
composed of two 1-symbol PUCCHs conveying the same UCI. Sequence
hopping between the two symbols may be supported and frequency
hopping may also be supported at least for a localized (contiguous)
PRB allocation in each symbol. Frequency-hopping for a PUCCH may
also occur within the active UL bandwidth part (BWP) for the UE.
The active BWP refers to BWP associated with the numerology of
PUCCH.
[0077] For short a PUCCH (e.g., 1-2 OFDM symbols) having a UCI
payload of greater than two bits, RS and UCI may be multiplexed in
a frequency division multiplexing (FDM) manner in the orthogonal
frequency division multiplexing (OFDM) symbols where RS and UCI are
mapped on different subcarriers and coherent demodulation is
supported.
[0078] In one aspect, encoded UCI bits are scrambled using an LTE
PN sequence generator initialized based on the scrambling ID for
the PUSCH. In one aspect, modulation of UCI may use quadrature
phase shift keying (QPSK).
[0079] In one aspect, the number of PRBs used for transmission may
be determined by the total number of UCI bits and/or the configured
maximum code-rate and/or be upper bounded by the configured number
of PRBs. In one aspect, localized (contiguous) allocations may be
supported.
[0080] In an aspect, the number of PRBs that are used for a PUCCH
may be configurable. In addition to RRC configuration, the number
of PRBs can be additionally determined as a function of UCI payload
size or by dynamic indication via DCI.
[0081] In an aspect, the number of DMRS resource elements (REs) per
PRB may be four, which provides a DMRS overhead of 1/3. In another
aspect, DMRS resource elements may be evenly distributed within a
PRB in subcarriers #1, #4, #7, #10 for a given resource block (RB),
as shown in FIG. 5A. For 2-symbol transmission, the same DMRS
density and pattern (e.g., the same DMRS locations) as a 1-symbol
short PUCCH with UCI payload greater than 2 bits can be used for
each symbol of the 2-symbol PUCCH, as shown in FIG. 5C. The
sequences used for DMRS may be the same as for cyclic prefix
(CP)-OFDM PUSCH DMRS, and may be obtained with an LTE PN sequence
generator.
[0082] For 2-symbol short-PUCCH with a UCI payload greater than 2
bits, the encoded UCI bits may be mapped across two symbols.
Additionally, frequency hopping may be supported. Frequency-hopping
for a PUCCH may occur within the active UL BWP for the UE and the
active BWP refers to a BWP associated with the numerology of a
PUCCH. Simultaneous transmission of HARQ-ACK bits and CSI feedback
with or without SR with PUCCH format 2 may also be supported by RRC
configuration.
[0083] In one aspect, there may be no additional RRC signaling
involved regarding how encoding is done for CSI/HARQ-ACK/SR. In one
aspect, whether some UCI is dropped or not may not be considered as
part of the encoding.
[0084] FIG. 5A is a diagram 500A illustrating an example DMRS used
in a short PUCCH format having a density corresponding to four
slots, e.g., slots 1, 4, 7, and 10. FIG. 5B is a diagram 500B
illustrating an example adjustment to the density of DMRS used in
the short PUCCH format of FIG. 5A. The adjustment reduces the
density from four slots to two slots. Alternatively, an adjustment
may also increase the density of slots being used.
[0085] FIG. 5C is a diagram 500C illustrating an example DMRS used
in a short PUCCH format having a location corresponding to four
slots, e.g., slots 1, 4, 7, and 10. FIG. 5D is a diagram 500D
illustrating an example adjustment to the location of DMRS used in
the short PUCCH format of FIG. 5C. The adjustment changes the
location of the slots being used to slots 2, 5, 8, and 11. Although
the illustrated adjustment shifts the slots in one direction, the
adjustment may alternatively shift the slots in the other
direction.
[0086] FIG. 6A is a flowchart 600 of a method of wireless
communication. The method may be performed by a UE (e.g., the UE
104, 350, 402; the apparatus 702). The method may enable the
adaptation of PUCCH communication within a slot (e.g., rather than
for repetitions over multiple slots). The adaptation may allow for
an increased payload over time with a more efficient use of
wireless resource. For example, using shorter PUCCH formats may
enable faster beam switching and a quicker response to changes in
channel conditions.
[0087] At 604, the UE receives from the base station an indication
of an adjustment to at least one of a density or a location of one
or more DMRS for at least one PUCCH format. FIG. 4 illustrates an
example of a UE 402 receiving an adjustment indication, at 410,
from a base station 404. The UE may make, e.g., apply, an
adjustment to the density or the location of DMRS for the at least
one PUCCH format in accordance with the indication. In one aspect,
604 may be performed by the indication component 742 and/in FIG.
7.
[0088] At 606, the UE transmits to the base station a PUCCH based
on the indication of the adjustment to at least one of the density
or the location of the one or more DMRS. In one aspect, 606 may be
performed by the PUCCH format component 740 and/or the transmission
component 734 in FIG. 7. FIG. 4 illustrates an example of a UE 402
transmitting a PUCCH 414 to the base station 404 based on the
indication of the adjustment, at 410. FIGS. 5A-5D illustrate
various aspects regarding a density or location of a DMRS for
PUCCH, which may be adjusted.
[0089] FIG. 6B illustrates a flowchart 650 of a method of wireless
communication that may include the reception, from the base
station, based on at least one of the CSI feedback or the uplink
transmission, an indication of an adjustment to at least one of a
density or a location of one or more DMRS for at least one PUCCH
format, at 604, and the transmission to the base station a PUCCH
based on the indication of the adjustment to at least one of the
density or the location of the one or more DMRS, at 606, as
described in connection with FIG. 6A.
[0090] As illustrated at 602 in FIG. 6B, the UE may transmit to the
BS at least one of CSI feedback or an uplink transmission. The
adjustment of the density or location of the DMRS(s) may be based
on the CSI feedback or the uplink transmission from the UE. In one
aspect, 602 may be performed by the transmission component 734 in
FIG. 7. The transmission of the CSI may be performed, e.g., by the
CSI component 744 of the apparatus 702 in FIG. 7. The transmission
of the uplink transmission may be performed, e.g., by the uplink
component 746 of the apparatus 702.
[0091] In one aspect, the adjustment to the density or the location
of the DMRS may be based on at least one of an uplink channel
measurement, a SINR, or a HARQ process. Such information may be
provided to the BS by the UE, for example, in the CSI feedback or
UL transmission.
[0092] In one aspect, the at least one PUCCH format is a short
PUCCH format may include one or more of PUCCH format 2, PUCCH
format 0, or PUCCH format 3. In one aspect, the adjustment to the
density or the location of the one or more DMRS may correspond to
an adjustment to a length of the at least one PUCCH format. In one
format the adjustment to the density of the DMRS may correspond to
an increase or a decrease in a number of OFDM symbols per slot. For
example, the number of OFDM symbols per slot can be increased or
decreased based on at least one of a coverage enhancement
indication or an ACK to a PDSCH.
[0093] In one aspect, the density or the location of the one or
more DMRS may correspond to one or more DMRS patterns. In one
aspect, the one or more DMRS patterns may be associated with a
contiguous set of OFDM symbols. Additionally, the adjustment to the
density or the location of the one or more DMRS may be configured
or defined. In some aspects, a change of DMRS density and/or
location may be linked to a change of a length of a PUCCH format
(e.g., PUCCH format 2) based on a rule or definition. In other
aspects, the change may be configured by the base station. For
example, the indication may correspond to one of a set of
preconfigured or predefined reconfigurations for a PUCCH. In some
aspects, the UE may receive a dynamic indication of a change in the
density and/or location of the DMRS of a PUCCH. In one aspect, the
indication may be received by the UE via one or more of a
UE-specific DCI or GC-DCI, or a MAC-CE. In some aspects, the UE may
receive the indication of a pattern of DMRS, e.g., from a set of
pattern options that may be configured or defined. The UE may
receive the indication of a switch among a set of reconfigurations
for the PUCCH. Thus, the UE may receive a change in a configuration
option for the PUCCH, then may receive an indication for the UE to
use the new configuration option. In some aspects, the UE may
receive the indication to change based on other signaling. For
example, the UE may receive the indication based on an increase in
the density and/or location of the DMRS for the PUCCH based on
transmission of a coverage enhancement indication. As another
example, the UE may switch the density and/or location of DMRS for
PUCCH (e.g., PUCCH format 0) if the PUCCH contains an ACK in
response to a PDSCH that carries a beam switching MAC-CE for the
UE.
[0094] FIG. 7 is a diagram 700 illustrating an example of a
hardware implementation for an apparatus 702. The apparatus 702 may
be a UE, a component of a UE, or may implement UE functionality. In
some aspects, the apparatus 702 may include a cellular baseband
processor 704 (also referred to as a modem) coupled to a cellular
RF transceiver 722. In some aspects, the apparatus 702 may further
include one or more subscriber identity modules (SIM) cards 720, an
application processor 706 coupled to a secure digital (SD) card 708
and a screen 710, a Bluetooth module 712, a wireless local area
network (WLAN) module 714, a Global Positioning System (GPS) module
716, and a power supply 718. The cellular baseband processor 704
communicates through the cellular RF transceiver 722 with the UE
104 and/or BS 102/180. The cellular baseband processor 704 may
include a computer-readable medium/memory. The computer-readable
medium/memory may be non-transitory. The cellular baseband
processor 704 is responsible for general processing, including the
execution of software stored on the computer-readable
medium/memory. The software, when executed by the cellular baseband
processor 704, causes the cellular baseband processor 704 to
perform the various functions described supra. The
computer-readable medium/memory may also be used for storing data
that is manipulated by the cellular baseband processor 704 when
executing software. The cellular baseband processor 704 further
includes a reception component 730, a communication manager 732,
and a transmission component 734. The communication manager 732
includes the one or more illustrated components. The components
within the communication manager 732 may be stored in the
computer-readable medium/memory and/or configured as hardware
within the cellular baseband processor 704. The cellular baseband
processor 704 may be a component of the UE 350 and may include the
memory 360 and/or at least one of the TX processor 368, the RX
processor 356, and the controller/processor 359. In one
configuration, the apparatus 702 may be a modem chip and include
just the cellular baseband processor 704, and in another
configuration, the apparatus 702 may be the entire UE (e.g., see
350 of FIG. 3) and include the additional modules of the apparatus
702.
[0095] The communication manager 732 includes an indication
component 742 that is configured to receive an indication of an
adjustment to the density or the location of DMRS for at least one
PUCCH format in accordance with an indication received from the BS,
e.g., as described in connection with 604 of FIG. 6A or 6B. The
apparatus 702 may include a CSI component 744 is further configured
to transmit CSI feedback transmission to the BS, e.g., as described
in connection with 602 of FIG. 6B. The apparatus 702 may include an
uplink component 746 configured to transmit an uplink transmission
to the BS, e.g., as described in connection with 602 in FIG. 6B.
The transmission component 734 and the PUCCH format component may
be configured to transmit a PUCCH to the BS using the adjusted
density or the adjusted location of DMRS for the at least one PUCCH
format, e.g., as described in connection with 606 of FIG. 6A or
6B.
[0096] The apparatus may include additional components that perform
each of the blocks of the algorithm in the flowcharts of FIG. 6A,
6B and/or the aspects performed by the UE in FIG. 4. As such, each
block in the flowcharts of FIG. 6A, 6B and/or the aspects performed
by the UE in FIG. 4 may be performed by a component and the
apparatus may include one or more of those components. The
components may be one or more hardware components specifically
configured to carry out the stated processes/algorithm, implemented
by a processor configured to perform the stated
processes/algorithm, stored within a computer-readable medium for
implementation by a processor, or some combination thereof.
[0097] As shown, the apparatus 702 may include a variety of
components configured for various functions. In one configuration,
the apparatus 702, and in particular the cellular baseband
processor 704, includes means for transmitting, to a base station,
at least one of CSI feedback or an uplink transmission; means for
receiving, from the base station based on at least one of the CSI
feedback or the uplink transmission, an indication of an adjustment
to at least one of a density or a location of one or more DMRS for
at least one PUCCH format; and means for transmitting to the base
station a PUCCH based on the indication of the adjustment to at
least one of the density or the location of the one or more DMRS.
The means may be one or more of the components of the apparatus 702
configured to perform the functions recited by the means. As
described supra, the apparatus 702 may include the TX Processor
368, the RX Processor 356, and the controller/processor 359. As
such, in one configuration, the means may be the TX Processor 368,
the RX Processor 356, and the controller/processor 359 configured
to perform the functions recited by the means.
[0098] FIG. 8A is a flowchart 800 of a method of wireless
communication. The method may be performed by a base station (e.g.,
the base station 102/180, 310, 404; the apparatus 902. The method
may enable the adaptation of PUCCH communication within a slot
(e.g., rather than for repetitions over multiple slots). The
adaptation may allow for an increased payload over time with a more
efficient use of wireless resource. For example, using shorter
PUCCH formats may enable faster beam switching and a quicker
response to changes in channel conditions.
[0099] At 808, the base station transmits an indication to the UE
of the adjustment to at least one of the density or the location of
the one or more DMRS for the at least one PUCCH format. In one
aspect, 804 may be performed by the indication component 944 in
FIG. 9 in accordance with the transmission component 934 in FIG. 9.
For example, the indication may be transmitted via at least one of
UE-specific DCI, GC-DCI, or a MAC-CE. FIG. 4 illustrates a base
station 404 transmitting an adjustment indication 410 to a UE 402.
FIG. 5A-5D illustrate various example aspects of density and
location for DMRS.
[0100] At 810, the base station monitors for PUCCH based on the
adjustment to the density or the location of the DMRS indicated to
the UE. For example, the base station may receive a PUCCH from the
UE based on the indication of the adjustment to at least one of the
density or the location of the one or more DMRS, e.g., as
illustrated in FIG. 4. In one aspect, 810 may be performed by the
reception component 930, the PUCCH format component 942, and/or the
DMRS component 940 in FIG. 9. For example, the received PUCCH form
the UE includes the adjusted density and/or the adjusted location
indicated in the indication.
[0101] FIG. 8B illustrates an example flowchart 850 of a method of
wireless communication that may include 808 and 810 of FIG. 8A. As
illustrated at 802, the base station may receive at least one of
CSI feedback or uplink transmission from a UE. The adjustment to
the at least one of the density or the location of the DMRS for the
PUCCH format may be based on the CSI feedback of the uplink
transmission from the UE. In one aspect, 802 may be performed by
the reception component 930, the CSI component 946, and/or the
uplink component 948 in FIG. 9.
[0102] At 804, the base station may determine to adjust at least
one of a density or a location of one or more DMRS for at least one
PUCCH format. The determination may include any of the aspects
described in connection with 408 in FIG. 4. In one aspect, 804 may
be performed by the DMRS component 940 in FIG. 9. For example, the
determination to adjust the density and/or the location of the one
or more DMRS can be based on at least one of an uplink channel
measurement, a SINR, or a HARQ process. Additionally, the
determination to adjust the density and/or the location of the one
or more DMRS can be based on information received from the UE or
other information not received from the UE.
[0103] In one aspect, the at least one PUCCH format is a short
PUCCH format including PUCCH format 2, PUCCH format 3, or PUCCH
format 0.
[0104] In one aspect, the adjustment to the density and/or the
location of the one or more DMRS corresponds to an adjustment to a
length of the at least one PUCCH format.
[0105] In one aspect, the adjustment to the density of the one or
more DMRS corresponds to an increase or a decrease in a number of
OFDM symbols per slot. For example, the number of OFDM symbols per
slot may be increased or decreased based on at least one of a
coverage enhancement indication or an ACK to a PDSCH.
[0106] In one aspect, at least one of the density or the location
of the one or more DMRS corresponds to one or more DMRS patterns.
For example, the one or more DMRS patterns can be associated with a
contiguous set of OFDM symbols.
[0107] In one aspect, the adjustment to the density or the location
of the one or more DMRS is preconfigured or predefined. For
example, the indication may correspond to one of a set of
preconfigured or predefined reconfigurations for a PUCCH.
[0108] In one aspect, the density or the location of the one or
more DMRS may correspond to one or more DMRS patterns. In one
aspect, the one or more DMRS patterns may be associated with a
contiguous set of OFDM symbols. Additionally, the adjustment to the
density or the location of the one or more DMRS may be configured
or defined. In some aspects, a change of DMRS density and/or
location may be linked to a change of a length of a PUCCH format
(e.g., PUCCH format 2) based on a rule or definition. In other
aspects, the change may be configured by the base station. For
example, the indication may correspond to one of a set of
preconfigured or predefined reconfigurations for a PUCCH. In some
aspects, the base station may dynamically change the density and/or
location of the DMRS of a PUCCH. In one aspect, the indication may
be transmitted to the UE via one or more of a UE-specific DCI or
GC-DCI, or a MAC-CE. In some aspects, the base station may indicate
a pattern of DMRS, e.g., from a set of pattern options that may be
configured or defined. The base station may indicate a switch among
a set of reconfigurations for the PUCCH. Thus, the base station may
change a configuration option for the PUCCH, then may indicate for
the UE to use the new configuration option. In some aspects, the
base station may indicate the change to the UE based on other
signaling. For example, the base station may indicate an increase
in the density and/or location of the DMRS for the PUCCH based on
transmission of a coverage enhancement indication. As another
example, the UE may switch the density and/or location of DMRS for
PUCCH (e.g., PUCCH format 0) if the PUCCH contains an ACK in
response to a PDSCH that carries a beam switching MAC-CE for the
UE.
[0109] FIG. 9 is a diagram 900 illustrating an example of a
hardware implementation for an apparatus 902. The apparatus 902 may
be a base station, a component of a base station, or may implement
base station functionality. In some aspects, the apparatus 902
includes a baseband unit 904. The baseband unit 904 may communicate
through a cellular RF transceiver 922 with the UE 104. The baseband
unit 904 may include a computer-readable medium/memory. The
baseband unit 904 is responsible for general processing, including
the execution of software stored on the computer-readable
medium/memory. The software, when executed by the baseband unit
904, causes the baseband unit 904 to perform the various functions
described supra. The computer-readable medium/memory may also be
used for storing data that is manipulated by the baseband unit 904
when executing software. The baseband unit 904 further includes a
reception component 930, a communication manager 932, and a
transmission component 934. The communication manager 932 includes
the one or more illustrated components. The components within the
communication manager 932 may be stored in the computer-readable
medium/memory and/or configured as hardware within the baseband
unit 904. The baseband unit 904 may be a component of the base
station 310 and may include the memory 376 and/or at least one of
the TX processor 316, the RX processor 370, and the
controller/processor 375.
[0110] The apparatus 902 may include a reception component 930, CSI
component 946, and/or uplink component 948 configured to receive
CSI feedback or a UL transmission from the UE and provide the
received information to the DMRS component 940, e.g., as described
in connection with 802 in FIG. 8B. The communication manager 932
includes a DMRS component 940 that is configured to determine to
adjust the density or the location of DMRS for one or more PUCCH
formats, e.g., as described in connection with 804 of FIG. 8B. The
communication manager 932 further includes an indication component
944 that is configured to adjust the density or the location of
DMRS for one or more PUCCH formats and transmit an indication of
the adjustment to the UE, e.g., as described in connection with 808
of FIG. 8A or 8B. The reception component 930 and/or the PUCCH
format component 942 may be further configured to monitor for a
PUCCH transmission from the UE with adjusted density or adjusted
location of DMRS based on the indication transmitted to the UE,
e.g., as described in connection with 810 in FIG. 8A or 8B.
[0111] The apparatus may include additional components that perform
each of the blocks of the algorithm in the flowcharts of FIGS. 8A,
8B, and/or the aspects performed by the base station in FIG. 4. As
such, each block in the flowcharts of FIGS. 8A, 8B, and/or the
aspects performed by the base station in FIG. 4 may be performed by
a component and the apparatus may include one or more of those
components. The components may be one or more hardware components
specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0112] As shown, the apparatus 902 may include a variety of
components configured for various functions. In one configuration,
the apparatus 902, and in particular the baseband unit 904,
includes means for transmitting, to the UE, an indication of the
adjustment to at least one of the density or the location of the
one or more DMRS for the at least one PUCCH format and means for
monitoring for PUCCH based on the adjustment to the density or the
location of the DMRS indicated to the UE. The apparatus may further
include means for determining to adjust at least one of a density
or a location of one or more DMRS for at least one PUCCH format;
means for adjusting at least one of the density or the location of
the one or more DMRS for the at least one PUCCH format based on at
least one of CSI feedback or an uplink transmission from a UE; and.
The means may be one or more of the components of the apparatus 902
configured to perform the functions recited by the means. As
described supra, the apparatus 902 may include the TX Processor
316, the RX Processor 370, and the controller/processor 375. As
such, in one configuration, the means may be the TX Processor 316,
the RX Processor 370, and the controller/processor 375 configured
to perform the functions recited by the means.
[0113] It is understood that the specific order or hierarchy of
blocks in the processes/flowcharts disclosed is an illustration of
example approaches. Based upon design preferences, it is understood
that the specific order or hierarchy of blocks in the
processes/flowcharts may be rearranged. Further, some blocks may be
combined or omitted. The accompanying method claims present
elements of the various blocks in a sample order, and are not meant
to be limited to the specific order or hierarchy presented.
[0114] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language claims,
wherein reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." Terms such as "if," "when," and "while" should be
interpreted to mean "under the condition that" rather than imply an
immediate temporal relationship or reaction. That is, these
phrases, e.g., "when," do not imply an immediate action in response
to or during the occurrence of an action, but simply imply that if
a condition is met then an action will occur, but without requiring
a specific or immediate time constraint for the action to occur.
The word "exemplary" is used herein to mean "serving as an example,
instance, or illustration." Any aspect described herein as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other aspects. Unless specifically stated
otherwise, the term "some" refers to one or more. Combinations such
as "at least one of A, B, or C," "one or more of A, B, or C," "at
least one of A, B, and C," "one or more of A, B, and C," and "A, B,
C, or any combination thereof" include any combination of A, B,
and/or C, and may include multiples of A, multiples of B, or
multiples of C. Specifically, combinations such as "at least one of
A, B, or C," "one or more of A, B, or C," "at least one of A, B,
and C," "one or more of A, B, and C," and "A, B, C, or any
combination thereof" may be A only, B only, C only, A and B, A and
C, B and C, or A and B and C, where any such combinations may
contain one or more member or members of A, B, or C. All structural
and functional equivalents to the elements of the various aspects
described throughout this disclosure that are known or later come
to be known to those of ordinary skill in the art are expressly
incorporated herein by reference and are intended to be encompassed
by the claims. Moreover, nothing disclosed herein is intended to be
dedicated to the public regardless of whether such disclosure is
explicitly recited in the claims. The words "module," "mechanism,"
"element," "device," and the like may not be a substitute for the
word "means." As such, no claim element is to be construed as a
means plus function unless the element is expressly recited using
the phrase "means for."
[0115] Aspect 1 is a method of wireless communication of a base
station. The method includes determining to adjust at least one of
a density or a location of one or more DMRS for at least one PUCCH
format. The method includes adjusting at least one of the density
or the location of the one or more DMRS for the at least one PUCCH
format based on at least one of CSI feedback or an uplink
transmission from a UE. The method also includes transmitting, to
the UE, an indication of the adjustment to at least one of the
density or the location of the one or more DMRS for the at least
one PUCCH format.
[0116] Aspect 2 is the method of aspect 1, where the at least one
PUCCH format is a short PUCCH format including PUCCH format 2 or
PUCCH format 3.
[0117] Aspect 3 is the method of any of aspects 1 and 2, where the
adjustment to at least one of the density or the location of the
one or more DMRS corresponds to an adjustment to a length of the at
least one PUCCH format.
[0118] Aspect 4 is the method of any of aspects 1 to 3, where the
adjustment to the density of the one or more DMRS corresponds to an
increase or a decrease in a number of orthogonal frequency division
multiplexing (OFDM) symbols per slot.
[0119] Aspect 5 is the method of any of aspects 1 to 4, where the
number of OFDM symbols per slot is increased or decreased based on
at least one of a coverage enhancement indication or an
acknowledgement (ACK) to a physical downlink shared channel
(PDSCH).
[0120] Aspect 6 is the method of any of aspects 1 to 5, where at
least one of the density or the location of the one or more DMRS
corresponds to one or more DMRS patterns.
[0121] Aspect 7 is the method of any of aspects 1 to 6, where the
one or more DMRS patterns are associated with a contiguous set of
orthogonal frequency division multiplexing (OFDM) symbols.
[0122] Aspect 8 is the method of any of aspects 1 to 7, further
comprising receiving, from the UE, at least one of the CSI feedback
or the uplink transmission.
[0123] Aspect 9 is the method of any of aspects 1 to 8, further
comprising receiving, from the UE, a PUCCH based on the indication
of the adjustment to at least one of the density or the location of
the one or more DMRS.
[0124] Aspect 10 is the method of any of aspects 1 to 9, where the
adjustment of the at least one of the density or the location of
the one or more DMRS is further based on at least one of an uplink
channel measurement, a signal-to-interference plus noise ratio
(SINR), or a hybrid automatic repeat request (HARD) process.
[0125] Aspect 11 is the method of any of aspects 1 to 10, where the
indication corresponds to one of a set of reconfigurations for a
PUCCH.
[0126] Aspect 12 is the method of any of aspects 1 to 11, where the
indication is transmitted via at least one of UE-specific downlink
control information (DCI), group-common DCI, or a medium access
control (MAC) control element (MAC-CE).
[0127] Aspect 13 is the method of any of aspects 1 to 12, where the
adjustment to at least one of the density or the location of the
one or more DMRS is preconfigured or predefined.
[0128] Aspect 14 is an apparatus for wireless communication at a
base station including means for implementing a method as in any of
aspects 1 to 13.
[0129] Aspect 15 is an apparatus for wireless communication
including at least one processor coupled to a memory and configured
to implement a method as in any of aspects 1 to 13.
[0130] Aspect 16 is a computer-readable medium storing computer
executable code, where the code when executed by a processor causes
the processor to implement a method as in any of aspects 1 to
13.
[0131] Aspect 17 is a method of wireless communication of a user
equipment. The method includes transmitting, to a base station, at
least one of channel state information (CSI) feedback or an uplink
transmission. The method includes receiving, from the base station
based on at least one of the CSI feedback or the uplink
transmission, an indication of an adjustment to at least one of a
density or a location of one or more demodulation reference signals
(DMRS) for at least one physical uplink control channel (PUCCH)
format. The method also includes transmitting to the base station a
PUCCH based on the indication of the adjustment to at least one of
the density or the location of the one or more DMRS.
[0132] Aspect 18 is the method of aspect 17, where the at least one
PUCCH format is a short PUCCH format including PUCCH format 2 or
PUCCH format 3.
[0133] Aspect 19 is the method of any of aspects 17 to 18, where
the adjustment to at least one of the density or the location of
the one or more DMRS corresponds to an adjustment to a length of
the at least one PUCCH format.
[0134] Aspect 20 is the method of any of aspects 17 to 19, where
the adjustment to the density of the one or more DMRS corresponds
to an increase or a decrease in a number of orthogonal frequency
division multiplexing (OFDM) symbols per slot.
[0135] Aspect 21 is the method of any of aspects 17 to 20, where
the number of OFDM symbols per slot is increased or decreased based
on at least one of a coverage enhancement indication or an
acknowledgement (ACK) to a physical downlink shared channel
(PDSCH).
[0136] Aspect 22 is the method of any of aspects 17 to 21, where at
least one of the density or the location of the one or more DMRS
corresponds to one or more DMRS patterns.
[0137] Aspect 23 is the method of any of aspects 17 to 22, where
the one or more DMRS patterns are associated with a contiguous set
of orthogonal frequency division multiplexing (OFDM) symbols.
[0138] Aspect 24 is the method of any of aspects 17 to 23, where
the adjustment to at least one of the density or the location of
the one or more DMRS is based on at least one of an uplink channel
measurement, a signal-to-interference plus noise ratio (SINR), or a
hybrid automatic repeat request (HARD) process.
[0139] Aspect 25 is the method of any of aspects 17 to 24, where
the indication corresponds to one of a set of reconfigurations for
a PUCCH.
[0140] Aspect 26 is the method of any of aspects 17 to 25, where
the indication is received via at least one of UE-specific downlink
control information (DCI), group-common DCI, or a medium access
control (MAC) control element (MAC-CE).
[0141] Aspect 27 is the method of any of aspects 17 to 26, where
the adjustment to at least one of the density or the location of
the one or more DMRS is preconfigured or predefined.
[0142] Aspect 28 is an apparatus for wireless communication
including means for implementing a method as in any of aspects 17
to 27.
[0143] Aspect 29 is an apparatus for wireless communication
including at least one processor coupled to a memory and configured
to implement a method as in any of aspects 17 to 27.
[0144] Aspect 30 is a computer-readable medium storing computer
executable code, where the code when executed by a processor causes
the processor to implement a method as in any of aspects 17 to
27.
[0145] Aspect 31 is a method of wireless communication of a base
station, comprising: transmitting, to a UE, an indication of an
adjustment to at least one of a density or a location of one or
more DMRS for at least one PUCCH format; and monitoring for PUCCH
based on the adjustment to the density or the location of the DMRS
indicated to the UE.
[0146] In aspect 32, the method of aspect 31 further includes
receiving at least one of CSI feedback or an uplink transmission
from the UE, the adjustment to the at least one of the density or
the location of the DMRS for the at least one PUCCH format being
based on the CSI feedback of the uplink transmission from the
UE.
[0147] In aspect 33, the method of aspect 31 or aspect 32 further
includes that the at least one PUCCH format is a short PUCCH format
including PUCCH format 2 or PUCCH format 3.
[0148] In aspect 34, the method of any of aspects 31-33 further
includes that the adjustment to at least one of the density or the
location of the one or more DMRS corresponds to a length adjustment
of the at least one PUCCH format.
[0149] In aspect 35, the method of any of aspects 31-34 further
includes that the adjustment to the density of the one or more DMRS
corresponds to an increase or a decrease in a number of OFDM
symbols per slot.
[0150] In aspect 36, the method of aspect 35 further includes that
the number of OFDM symbols per slot is increased or decreased based
on at least one of a coverage enhancement indication or an ACK to a
PDSCH.
[0151] In aspect 37, the method of any of aspects 31-36 further
includes that at least one of the density or the location of the
one or more DMRS corresponds to one or more DMRS patterns.
[0152] In aspect 38, the method of aspect 37 further includes that
the one or more DMRS patterns are associated with a contiguous set
of OFDM symbols.
[0153] In aspect 39, the method of any of aspects 31-38 further
includes receiving, from the UE, the PUCCH based on the indication
of the adjustment to at least one of the density or the location of
the one or more DMRS.
[0154] In aspect 40, the method of any of aspects 31-39 further
includes that the adjustment of the at least one of the density or
the location of the one or more DMRS is further based on at least
one of an uplink channel measurement, a SINR, or a HARQ
process.
[0155] In aspect 41, the method of any of aspects 31-40 further
includes that the indication corresponds to one of a set of
reconfigurations for the at least one PUCCH format.
[0156] In aspect 42, the method of any of aspects 31-41 further
includes that the indication is transmitted via at least one of
UE-specific DCI, group-common DCI, or a MAC-CE.
[0157] In aspect 43, the method of any of aspects 31-42 further
includes that the adjustment to at least one of the density or the
location of the one or more DMRS is preconfigured or
predefined.
[0158] Aspect 44 is an apparatus for wireless communication
including at least one processor coupled to a memory, the memory
and the at least one processor configured to perform the method of
any of aspects 31-43.
[0159] In aspect 45, the apparatus of aspect 44 further includes at
least one of an antenna or a transceiver coupled to the at least
one processor.
[0160] Aspect 46 is an apparatus for wireless communication
including means for performing the method of any of aspects
31-43.
[0161] In aspect 47, the apparatus of aspect 46 further includes at
least one of an antenna or a transceiver.
[0162] Aspect 48 is a non-transitory computer-readable medium
storing computer executable code, where the code when executed by a
processor causes the processor to implement any of aspects
31-43.
[0163] Aspect 49 is a method of wireless communication of a UE,
comprising: receiving, from a base station, an indication of an
adjustment to at least one of a density or a location of one or
more DMRS for at least one PUCCH format; and transmitting to the
base station a PUCCH based on the indication of the adjustment to
at least one of the density or the location of the one or more
DMRS.
[0164] In aspect 50, the method of aspect 49 further includes
transmitting, to a base station, at least one of CSI feedback or an
uplink transmission, the adjustment to the at least one of the
density or the location of the one or more DMRS for the at least
one PUCCH format being based on the CSI feedback or the uplink
transmission.
[0165] In aspect 51, the method of aspect 49 or aspect 50 further
includes that the at least one PUCCH format is a short PUCCH format
including PUCCH format 2 or PUCCH format 3.
[0166] In aspect 52, the method of any of aspects 49-51 further
includes that the adjustment to at least one of the density or the
location of the one or more DMRS corresponds to a length adjustment
of the at least one PUCCH format.
[0167] In aspect 53, the method of any of aspects 49-52 further
includes that the adjustment to the density of the one or more DMRS
corresponds to an increase or a decrease in a number of OFDM
symbols per slot.
[0168] In aspect 54, the method of aspect 53 further includes that
the number of OFDM symbols per slot is increased or decreased based
on at least one of a coverage enhancement indication or an ACK to a
PDSCH.
[0169] In aspect 55, the method of any of aspects 49-54 further
includes that at least one of the density or the location of the
one or more DMRS corresponds to one or more DMRS patterns.
[0170] In aspect 56, the method of aspect 55 further includes that
the one or more DMRS patterns are associated with a contiguous set
of OFDM symbols.
[0171] In aspect 57, the method of any of aspects 49-56 further
includes that the adjustment to at least one of the density or the
location of the one or more DMRS is based on at least one of an
uplink channel measurement, a SINR, or a HARQ process.
[0172] In aspect 58, the method of any of aspects 49-57 further
includes that the indication corresponds to one of a set of
reconfigurations for the at least one PUCCH format.
[0173] In aspect 59, the method of any of aspects 49-58 further
includes that the indication is received via at least one of
UE-specific DCI, group-common DCI, or a MAC-CE.
[0174] In aspect 60, the method of any of aspects 49-59 further
includes that the adjustment to at least one of the density or the
location of the one or more DMRS is preconfigured or
predefined.
[0175] Aspect 61 is an apparatus for wireless communication
including at least one processor coupled to a memory, the memory
and the at least one processor configured to perform the method of
any of aspects 49-60.
[0176] In aspect 62, the apparatus of aspect 61 further includes at
least one of an antenna or a transceiver coupled to the at least
one processor.
[0177] Aspect 63 is an apparatus for wireless communication
including means for performing the method of any of aspects
49-60.
[0178] In aspect 64, the apparatus of aspect 63 further includes at
least one of an antenna or a transceiver.
[0179] Aspect 65 is a non-transitory computer-readable medium
storing computer executable code, where the code when executed by a
processor causes the processor to implement any of aspects
49-60.
* * * * *